from CNN

Why scientists say we need to send clocks to the moon — soon

By Jackie Wattles

Shown here is the old marble sundial at Palace Paco de Sao Miguel in Evora, Portugal. Sundials have kept humans on schedule for millennia.  Geography Photos/Universal Images Group/Getty Images

Perhaps the greatest, mind-bending quirk of our universe is the inherent trouble with timekeeping: Seconds tick by ever so slightly faster atop a mountain than they do in the valleys of Earth.

For practical purposes, most people don’t have to worry about those differences.

But a renewed space race has the United States and its allies, as well as China, dashing to create permanent settlements on the moon, and that has brought the idiosyncrasies of time, once again, to the forefront.

On the lunar surface, a single Earth day would be roughly 56 microseconds shorter than on our home planet — a tiny number that can lead to significant inconsistencies over time.

NASA and its international partners are currently grappling with this conundrum.

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